Rubbing machine



De; H. E. EARL ETAL 2,918,75

RUBBING MACHINE Filed April 24, 1957 3 Sheets-Sheet l Dec. 29, 1959 H. E. EARL ETAL RUBBING MACHINE 5 Sheets-Sheet 2 Filed April 24, 1957 w S m .Tm/m@ jYnfarQ/f.' farb ma eff wmljelt Dec. 29, 1959 H. E. EARL ETAL 2,918,761

RUBBING MACHINE Filed April 24, 1957 5 sheets-sheet s Irrl/e lfaffaws Howard/ faf vef'i wingers United States Patent O RUBBING MACHINE Howard E. Earl and Robert W. Hilgers, Rockford, Ill., assignors to Sundstrand Corporation, a corporation of Illinois Application April 24, 1957, Serial No. 654,935

Claims. (Cl. 51-170) rl`his invention relates to rubbing machines and particularly to a rubbing machine having a shoe mounted for movement in an orbital path.

The general object of this invention is to provide an improved new and novel rubb-ing machine.

Another object of the invention is to provide a rubbing machine that is light in weight, of simple construction and in which many of the parts of the machine are of simple metal stampings.

Other and further objects of the invention will be readi- -ly apparent from the following description of one embodiment `of the invention and the accompanying drawings illustrating this embodiment, in which:

Fig. l is a plan view of a rubbing machine embodying the invention.

Fig. 2 is a side elevation of the rubbing machine.

Fig. 3 is an end elevation of the machine taken from a right hand end of Figs. 1 and 2.

Fig. `4 is a sectional elevational view taken substantially through the longitudinal center of the machine.

Fig. 5 is a sectional elevation-al view taken substantially along line 5 5 of Fig. 4.

Fig. 6 is la sectional plan view taken substantially along line 6 6 of Fig. 4.

Fig. 7 is a sectional elevational view taken substantially along line 7-7 of Fig. 3.

The rubbing machine shown in the -accompanying drawings comprises a rubbing shoe 10 that is mounted for orbital movement relative to a housing -11 which forms a part of a rotary pneumatic motor 12. The housing 11 has a rounded top 11a and inwardly curved sides 11b so that it may be held conveniently in the operators hand. A movable cover 13 also curved to fit the operators `hand is -pivoted on the housing around a pivot pin 14. The movable cover is arranged to control the operation of the unit in response to pressure applied to the cover.

The housing is provided with an air inlet 15 so that a lhose connection from a source of air under pressure may be attached to the inlet. Air flowing into the machine is controlled by means of a ball valve 16 of ordinary construction in which the b-all is held in closed position Iby means of a helical spring 17. The ball may be moved away from its seat by a plunger 18 provided with a rounded head 19 bearing against the under surface of the cover 13. Thus, depression of the cover 13 opens the valve 16 to cause air to flow into the motor 12. The motor 12 is an ordinary vane-type air motor. The motor is constructed and operates in the ordinary manner by air owing through the inlet 15 to rotate the vertical motor shaft 20.

The upper end of the motor shaft 20 extends into an upper chamber 21 in the housing 11 and has attached thereto by means of a screw 22 an upper counterweight. The upper end of the shaft 20 is journaled in a ball bearing structure 24. A single turn coil spring 25 is provided between the inner race 24a of the bearing and the bottom of the upper counterweight 23 as a 2 means cf preloading this bearing. This single turn spring therefore, serves to maintain a predetermined clearance above and below the rotor 12a of the motor.

The lower side of the housing 11 is provided with an outwardly extending ange 26 that forms a base on the housing. Arranged in the same plane as this flange and inwardly thereof is a bottom closure plate 27 for the motor. This closure 27 has extending downwardly there- Ifrom a generally circular flange 27a that houses the lower bearing 2S for the motor shaft 20.

The lower end of the shaft 20 beneath the bearing 28 is provided with a circular enlargement 20a.

Arranged beneath the enlargement 20a is an eccentric end 29 of the shaft 20. This eccentric end 29 is rotatably supported in a lower ball bearing structure 30 employ ing a double row of ball bearings. The lower end of the eccentric end 29 of the shaft is locked in position within the bearing structure by means of a threaded tapered plug 31 threaded into this lower end which is split into a plurality of sections by means of a series of slots 29af so that the thusly formed end sections are forced out# wardly from each other by the plug 31 into locking engagement with the ball bearing structure 30. The bottom of the eccentric end is provided with a retainingring 32 bearing against the bottom of the bearing structure 30.

Attached to the motor shaft enlargement 20a as by means of a set screw 33 is a lower counterweight 34. The two counterweights 23 and 24 mounted on the shaft 20 are arranged opposite to each other so as to provide `dynamic balance.

The rubbing shoe assembly comprises an elongated rectangular plate 35 having a depressed center portion 35a. elongated ribs 35C. The plate 35 has molded thereto` a rectangular block of resilient rubber 36 ink which the major portion of the rubber is adhered to the bottom 'of the plate 35 but with end portions 36a of the rubber block located on top of the ends of the plate. This rubber block 36 has a generally at bottom surface to which is attached a resilient pad 37 which may be felt, as shown, sponge rubber or other resilient material. A strip 38 of sandpaper or the like may be arranged as shown in Fig. 4 along the bottom of the rubbing shoe with ends 38a of the sandpaper strip held by releasable clamps 39 mounted on the ends of the rectangular plate' 35 as by rivets or the like.

Located Within the center portion 35a of the plate 35 is `a plate member 42 having its ends 42a curved upwardly to it the correspondingly curved ends of the depressed center portion 35a. This plate member 42'has its `center portion cut out to provide a circular opening andl a downwardly extending circular ange 42b. In this opening there is attached, as by soldering or the like, an:

upwardly extending cylindrical sleeve 41. This sleeve 41 is positioned around the lower ball bearing structure 30 to provide a pres-s` tit and in which the eccentric end 29 is positioned.

The plate member has its upturned outer edges 42a normally arranged in internested relationship with the central part 35a of the shoe plate 35.

The shoe assembly 10 is held spaced from the housing 11 but movable relative thereto by means of four helical springs 43. These springs are maintained under compression at all times by the following means: Each spring has its upper end attached to an upper threaded stud 44, threads of which are held within the upper convolutions of its spring. Each upper threaded stud 44 is held in the base flange 26 as by means of a rivet 45.

In addition, the lower end of each spring 43 is similarly held by similar lower threaded stud 46. Each lower stud 46 is held in position by means of a bolt 47. Each bolt The plate has a depressed center well 35b and- E has its head within a well 37a in the pad 37 and the bolt extends upwardly through the shoe plate 35 and the plate member 42 to engage a downward extension 45a of the lower stud 46. These operate as spacers to hold the sleeve ange under compression. With this arrangement the rubbing shoe assembly is attached to the lower end of the motor shaft by means of the four bolts 47, the plate member 42, the sleeve 41 and the lower bearing structure 30. The free lengths of the springs 43 when uncompressed are greater than the distance between the base plate member 50 that is beneath the housing 20 and the shoe plate member 42 at all working positions of the shoe 10 so that the four helical springs 43 which resiliently support the portions of the shoe assembly outwardly of the eccentric end 29 are always under compression. These compressed springs permit orbital movement of the shoe assembly on rotation of the shaft 20 but prevent rotation of the shoe assembly on rotation of the shaft.

The combinations of the screws 47, the shoe plate 35, and the plate member 42 also serve to clamp the lower end of a exible dust enclosure 48 in position. This flexible dust enclosure is of generally tubular shape and is rectangular in cross section. It is preferably made of exible rubber or rubber-like material. The enclosure forms no part of the shoe assembly support but is used only to enclose the lower operating parts of the rubbing machine. The two ends of the enclosure are provided with small holes 43a which will operate as air discharge holes. The lower edge of the enclosure 48 is provided with an inwardly directed ange portion 49 which is located between the shoe plate and the outer extremities of the plate member 42 and through which the stud extensions 46a pass. The upper edge of the enclosure 48 is provided with a preformed lip 48]) that is arranged to snap over an upwardly extended flange 50a of a base plate member 5() that extends beneath the base 26 of the housing lill. The upper ends of the springs 43 are adjacent to this plate member 50 which are provided with four radiating ribs 50b.

Within the sleeve 4l and beneath the lower bearing structure 30 there is provided a bearing seal plate 5l operating as a lubricant retainer for this lower bearing.

As can be seen from the above description, the number of parts of the shoe supporting and drive structure of the rubbing machine of this invention is kept to a minimum. This results in a lightweight structure that is easy to build and convenient to operate. In addition, the structure is made as simple as possible with certain of the parts performing a plurality of functions. The springs 43 which are equally spaced around the shaft 20 are maintained under compression at all times so as to provide a rm yet resilient force. These springs permit full movement of the shoe structure 10 but prevent rotation of the shoe structure on rotation of the motor shaft. The enclosure 4S forms no part of this motion resisting apparatus as this is solely a dust enclosure to protect the operating parts of the machine that are between the housing base 26 and the shoe structure 10.

As also pointed out previously, the ends of the sandpaper strip 38 or similar material are releasably held by a pair of end clamps 39. Each end clamp comprises a transverse base plate 52 attached to the plate 35 and having upturned substantially parallel end brackets 53. Extending between these brackets 53 and attached thereto are a pair of pins 54 and 55. The pin 54 nearer to the end of the shoe 10 is somewhat higher than is the rear pin 55. This forward pin 54 has rotatably mounted thereon a clamp member 56. This clamp member is provided with an end portion 57 having an outwardly curved lower lip 57a and a pair of rearwardly extending spaced substantially parallel ears 57b through which the forward pin 54 extends. Each ear 57h is adjacent to an end bracket 53.

The clamp member also includes a rearwardly extending top portion 58 that extends rearwardly of the portion 57 and that is at right angles thereto. This top portion 58 has a central cutout section 58a through which extends an actuating lever 59 of a support plate 60. This support plate is rotatably mounted about the rear pin 55. The support plate is provided with shoulders 60a on either side of the actuating lever 59 and adapted to bear against the bottom of the top portion 58 when the lever is in fully raised position as shown in Fig. 7, for example. The support plate 60 at the opposite end edges thereof is provided with rearwardly extending ears 6017 to operate as levers to start the clamping rotation of the clamp member 56 on movement of the member 59.

Located around the forward pin 54 of each clamp member 39 is a coil spring 61. One end 6M of this spring is anchored in the shoe structure l0. The other end 61h bears upwardly and outwardly against the bottom of the forward end portion 57 of the clamp member S6. The spring 61, therefore, operates to open the clamp member 56 when the lever 59 is moved to open position.

With this construction of the clamps each end of the sandpaper strip 38 is locked tightly in position by the lips 57a pressing downwardly against the end. The lip is held in this engagement by the support plate 60 bearing upwardly against the bottom of the clamp member S6. As the clamp member 56 is of spring steel construction it operates as a spring clamp.

As can be seen from the above description, many of the parts of the rubbing machine of this invention are made of sheet metal stampings. These include not only the members 52, 53, 56, 59 and 60 and associated portions of the clamps, but includes also the shoe plate member 35, plate member 42 and base plate member 50. Thus the parts are inexpensive to produce and the resulting structure is of lightweight yet sturdy construction.

Having described our invention as related to the ernbodiment shown in the accompanying drawings, it is our intention that the invention be not limited by any of the details o'f description unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claims.

We claim:

l. A rubbing machine, comprising: a rubbing shoe; a power driven motor abo've the shoe; shoe supporting spaced spring means adjacent the sides of the shoe extending between the motor and the shoe and distortable laterally to provide lateral movement of the shoe relative to the motor, the springs means being substantially the sole shoe supports located at said sides; said motor and shoe being spaced apart a distance sufficient to maintain the spring means under compression at all times; a motor shaft rotatated by said motor having one end extending toward the shoe; an eccentric on said shaft journalled in the shoe to cause orbital movement thereof against the resistance o'f the compressed spring means upon rotation of said motor shaft; a flexible dust enclosure extending between the motor and the shoe and surrounding the spring means and the eccentric; and means for attaching the dust enclosure to the shoe.

2. A rubbing machine, comprising: a rubbing shoe, a power driven motor above the shoe; sho'e supporting spaced spring means adjacent the sides of the shoe extending between the motor and the shoe and distortable laterally to provide lateral movement of the shoe relative to the motor, the spring means being substantially the sole shoe supports located at said sides; said motor and shoe being spaced apart a distance sucient to maintain the spring means under compression at all times; a motor shaft rotated by said motor having one end extending toward the sho'e; an eccentric on said shaft journalled in the shoe to cause .orbital movement thereof against the resistance of the compressed spring means upon rotation of said motor shaft; a exible dust enclosure extending between the bottom .of the motor and the shoe surround` ing the spring means and the eccentric and having an inturned flange portion at its shoe end; and means for clamping said flange portion to the shoe including a pair of plate members arranged on opposite sides of said flange portion.

3. A rubbing machine, comprising: a rubbing shoe; a power driven motor above the shoe having a base at its lower end; shoe supporting spaced helical springs extending between the motor and the shoe and distortable laterally upon lateral movement of the shoe relative to the motor; means fo'r attaching one end of each spring to said base; means for attaching the opposite end of each spring to the shoe; said motor and shoe being spaced apart a distance suflicient to maintain said springs under compression at all times; a motor shaft rotated by said motor having o'ne end extending toward the shoe; an eccentric on said one of the shaft; a flexible dust enclosure extending between the bottom of the motor and the shoe surrounding the spring means and the eccentric and having an inturned flange portion at its shoe end; a sleeve surrounding the eccentric in which said eccentric is rotatably mounted; a plate member attached to' said sleeve; a second plate member; and means for simultaneously clamping said plate members together with said dust enclosure flange therebetween and attaching the eccentric to the shoe.

4. A rubbing machine, comprising: a rubbing shoe; a power driven motor above the shoe having a base at its lower end; shoe supporting spaced helical springs extending between the moto'r and the shoe and distortable laterally upon lateral movement of the shoe relative to the motor, said motor and shoe being spaced apart a distance sulcient to maintain said springs under compression at all times; means for attaching one end of each spring to said base including an upper threaded stud received internally of said end; means for attaching the opposite end of each spring to the shoe including a lower threaded stud received internally of said end; a motor shaft rotated by said motor having one end extending toward the shoe; an eccentric on said one end of the shaft; a sleeve surrounding the eccentric in which said eccentric is rotatably mo'unted; a flexible dust enclosure extending between the bottom of the motor and the shoe surrounding the spring means and the eccentric and having an inturned flange portion at its shoe end; a plate member attached to said sleeve; means attaching said sleeve and thus said plate member to the eccentric with said helical springs under compression; a second plate member; and attaching means passing through said shoe and first and second plate members and engaging said lower threaded studs fo'r clamping said plate members with said dust enclosure flange therebetween, anchoring the lower ends of said springs to the shoe and attaching said eccentric to the shoe.

5. A rubbing machine, comprising: a rubbing shoe including a plate member having sections encased in a block of rubber extending over the bottom of said plate member; a power driven moto'r above the shoe including a housing having an outwardly extending bottom flange forming a base; a base plate member on the bottom of said base having upturned edges located beyond said base; a plurality of shoe supporting spaced helical springs extending between said base flange and the shoe and distortable laterally upon lateral movement of the shoe relative to the motor, said motor and shoe being spaced apart a distance sufficient to maintain said springs under compression at all times; an upper threaded stud attached to said base and located within the upper end of each spring anchoring said end to the base; a lower threaded stud located Within the lower end o'f each spring for anchoring the lower end of said spring; a motor shaft rotated by said motor having one end extending toward the shoe; an eccentric on said one end of the shaft; a cylindrical bearing around said eccentric; a cylindrical sleeve around said bearing; a bearing seal plate extending across said sleeve beneath the bearing; a plate member attached to said sleeve; a flexible dust enclosure o'f generally tubular shape having a preformed top edge lip engaging said upturned edges of said base plate member for anchoring the top edge of the dust enclosure and an inturned bottom flange, a bottom flange being located between the sleeve plate member and shoe plate member, the lower threaded studs each being provided with an extension o'n the bottom thereof extending through the sleeve plate t References Cited in the file of this patent UNITED STATES PATENTS 2,697,897 Dickinson Dec. 28, 1954 FOREIGN PATENTS 697,685 Great Britain Sept. 30, 1953 

